The present invention generally relates to a feeding arrangement and more particularly, to an automatic feeding arrangement of original documents for use in a copying apparatus and the like, which is so arranged to transport an original document over an original document platform or platen (referred to as a platen hereinafter) on which the original document is placed for exposure, and to automatically stop the original document upon arrival thereof at a predetermined copying position, and also, to automatically discharge the original document simultaneously upon completion of the copying.
Generally, the automatic original document feeding arrangement for a copying apparatus includes a sheet feeding mechanism and a sheet transport mechanism, and in order to meet the recent increasing demand for automatically copying a large number of original documents, with a subsequent sorting or classification thereof, there have been conventionally proposed various original document feeding arrangements and sorters. Under the circumstances as described above, particular importance is attached to the function of automatically stopping the original documents being transported, correctly at a predetermined copying position.
For stopping the original documents at the predetermined position as described above, there have already been proposed several systems as follows.
(i) A system for mechanically stopping the original document being transported, by a stopper member. PA0 (ii) A system in which the original document is once caused to pass through a predetermined position on an original document placing platen, and thereafter, returned to the predetermined position by moving an original document transport belt in a reverse direction. PA0 (iii) A system in which, during insertion of an original document, the leading edge thereof is detected so as to be advanced up to a predetermined position by a timing monitor. PA0 (iv) A system in which the leading edge of an original document is detected by a reflection type photo-electric sensor so as to be stopped at a predetermined position.
Each of these known systems, however, has an advantage or disadvantage inherent therein, and can not be regarded as perfect.
More specifically, in the system (i), in the case of a very thin original document, there is a possibility that the original document becomes wrinkled when mechanically stopped by the stopper member, and the system (ii) is rather inefficient since the original document transport belt functions in three stages of advance.fwdarw.retreat.fwdarw.advance, with a certain difficulty in design, while the system (iii) is not free from the drawback that an error in stopping at the predetermined position is increased, since a distance from the detecting position to the stopping position of the original document is too long. Further, in the system (iv), although the disadvantages as described in the foregoing may be eliminated, the detecting portion can not be covered by an original document transport belt, since the transport belt is not transparent and the leading edge of the original document is arranged to be detected through a light reflection system, and thus, there is a disadvantage such that the original document is transported, with a part thereof protruding from the transport belt.